Portable visual display device with a collapsible presentation screen

ABSTRACT

A colapsible rear projectrion screen assembly for a portable visual display device. Embodiments are presented that include a flexible screen supported by a surrounding rigid screen that collapses by a ssimple folding movement for easy transport while also removing any risk of opticql or physical damage to the screen member material in the collapsing process.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a presentation screen for the presentation ofstill or moving visual images such as pictures, text or data to a groupor a number of people in typical and everyday business, training,education, promotion or exhibition environments. The screen is of thediffusion type, using diffusion means for displaying the images on thefront viewing surface. The screen may collapse into a smallerconfiguration such as to significantly increase its portability asrequired for being readily moved from room to room or travelling fromplace to place. The field of the invention also relates to the variousforms of art that may be employed in its various embodiments as, or aspart of, a visual display device.

The field of this invention is that of flexible, rear projection screensand is not intended to include front (i.e. reflective) display screenapplications, active display screens or rigid screens.

2. Description of Prior Art

Visual Display by means of cathode ray tube (CRT) devices is commonlyused for computer monitors and televisions and can have relatively largescreens (up to 40 inch, 1 meter) but these are bulky and very heavy andthus not truly portable.

Visual display by rear projection such as in TV units can provide alarge screen area but such devices are not yet common and again thedevices are large and bulky and thus not truly portable.

Visual display devices using a Liquid Crystal Display (LCD) are commonparticularly in laptop computers and are highly portable but theirlimited screen size (14 inch, 35 cm) makes them unsuitable forpresentational use involving several persons viewing the screensimultaneously in comfort.

Various other displays are appearing such as plasma screens that arelarge screen (up to 42 inch currently, 105 cm) and that are almost flatfor hanging on a wall, but again are relatively heavy and bulky so nottruly portable.

Visual display by large screen front projection means is popular inbusiness and at home. Use may be in circumstances of a fixed set-up in aspecial room or for use in a portable or travelling manner. However thelatter requires some preparation—possibly in front of a waiting clientor audience. Depending on circumstances it may require suitable lightingconditions, a screen and the physical space to the projector screen tobe available. This can be a further disadvantage when associated withuse where visiting in a business environment since it may be consideredprofessionally “intrusive”, to impose these requirements on a clienteven for informal presentations.

Many visual display devices have tried to employ the advantages of thesystems above within a more or less portable package. In general theseare subject to the limitations either that the viewable screen issmaller than the case within which it is carried, or where the displayscreen is larger than the case and in some way disassembled for storageand carriage, use of the screen requires user intervention to thenassemble the screen and attach it to other required elements which isagain an inconvenience and takes time.

There are known methods for the collapsing of seamless front projectionscreens that employ flexible screens which fold away for storage.However these collapsing methods have not generally proved applicable intranslucent diffusion applications for the reasons set out below.

Front Projection screens are not translucent and therefore typicallyconsist of a reflective front surface with a reinforced backing thatprovides considerable physical “body” to the material such that it doesnot require to be stretched to operate or reflect lightuniformly—although it may be hung or stretched to stay in anapproximately planar condition. Further, physical damage such as creasesor folds in the screen surface are not highly critical to the opticalperformance as no light passes through the-material.

Flexible screens suitable for use in say a portable rear projectionapplication, are by necessity of their unique optical transmissive andcontrolled diffusive requirements, very thin, of a totally differenttranslucent and very homogeneous material without any reinforcing layer,must be under at least minimal tension and physical distortion andnon-planarity must be avoided. Further, any crease or fold of thematerial (even if not still physically present or not) may cause opticaldistortion to the passing light and images or cause “rainbow effect” or“white spots” and result in very irritating screen flaws to a viewer.

As a result, the technology of the screen, its material and also theoptical and physical requirements in use are very different from thoseapplicable to reflection screens. Further the demands of preserving thescreen optical qualities and screen longevity (especially in requiredhighly repeated or rapid opening and closing actions) are much morecritical in “fit for purpose” concerns. In consequence particulardifficulties are encountered in developing collapsible screens of thistype, and it has not been generally possible to apply collapsibleconcepts from the reflection screen art to screens designed for theapplication of the present invention.

Specifically, relevant prior art is list here:

D1: U.S. Pat. No. 4,323,301 (Spector D.) Apr. 6, 1982 A collapsible andportable flexible screen erected by inflating by gas cartridge a tubularrectangular loop.

D2: EP-A-0 424 074 (Failla S.) Apr. 24, 1991 Segmented rigid displayscreens that are collapsible by hinging/sliding means.

D3: EP-A-0676 893 (Projectavision Inc) Oct. 11, 1995 Cabinet forportable rear-screen television projector that features a light shield.

D4: U.S. Pat. No. 2,827,955 (Hurley A.) Mar. 25, 1958 Folding MotionPicture Screen (front projection only).

OBJECTS OF THE INVENTION

Accordingly:

It is an object of the present invention that it generates the viewableoptical images on the front viewing surface of the presentation screenby the diffusion of the light comprising of images that originate from alight source at a distance to the rear of the front viewing surface.

It is an object of the present invention that it provides a visualdisplay screen with a viewable surface area that is sufficiently largesuch that it may be readily and comfortably viewed by several people.

It is an object of the present invention that it may be viewed intypical in-door environments without need for further space or apparatus(other than if an external media source is required).

It is an object of the present invention that the screen assembly iscollapsible such that the viewable screen area is considerably largerwhen in an open condition than its largest area of encumbrance when in aclosed condition thus providing a portable nature suitable for carryingfrom room to room or for travelling from place to place.

It is an object of the present invention that it provides a visualdisplay screen that presents a joint-less and essentially planar screento a viewer situated in front of the viewing surface.

It is a desirable object of the present invention that it may beconsidered as “self-collapsing” that is to say that it can be deployedor collapsed as an integral assembly whereby the screen assembly doesnot require user intervention such that any parts be removed, added,attached, detached, re-located, tightened or loosened and requiring onlya simple and direct opening or closing action.

It is an object of the present invention that it employs specific meansor methods such as jointing means, mechanisms, elements, materials,shapes or geometrical configurations that are intended by their presenceor operation or action to prevent or reduce any damage or deteriorationof a physical or optical nature that may occur to the viewable screenarea due to any single or occasional or often repeated action ormovements or sustained positions of the collapsible screen assembly.

It is a desirable object of the present invention as, or as part of, aportable visual display device, to be readily and rapidly deployable toa useable state within a set-up time of several seconds.

It is a desirable object of the present invention as, or as part of, aportable visual display device, that it comprises true portability in ahand portable case.

Briefly stated, the objects of the present invention relate to aportable screen for presentation purposes that can be used as, or aspart of, a visual display device that is practically and commerciallysuitable in its various embodiments for making presentations of abusiness, professional, promotional, marketing, advertising,communication, training or educational nature to many people situated innormally lit indoor environments such as in typical businessenvironments, meeting rooms or offices, classrooms, lecture-rooms,exhibition halls, point-of-sale areas, gymnasiums etc., A possibleembodiment of the invention is as an optional accessory to conventionalprojectors.

SUMMARY OF THE INVENTION

In accordance with the principles of the present invention, theforegoing and other objects are achieved by a screen assembly composed asurrounding rectangular frame member to which is permanently attached aviewable screen member composed of a material that is attached andsupported within the said frame member. The screen member acts as adisplay screen by the diffusion of images on a front viewing surface,the images being produced by light-imaging elements or devices locatedto the rear of the forward facing viewing surface. The screen assemblyincludes jointing means permitting it to move as an assembly between twoconditions such that it can be rapidly opened and used as a displaydevice or rapidly collapsed into a closed condition that represents amuch smaller configuration suitable for ready transport or storage.

Accordingly, a screen assembly for a portable visual display devicecomprises a frame member to which is permanently attached a screenmember for the presentation of visual images on a front viewing surfaceto persons located on a viewing side by diffusion of optical imagescreated to the rear of this front viewing surface (which is to sayimages that may originate from a distance from the rear of the screen,but which excludes reflecting screen front projection) wherein thescreen assembly comprises at least two screen and frame sectionsconnected by jointing means such that the screen assembly is deployableinto a closed condition in such a manner as to significantly reduce thescreen member area when in the closed condition.

Thus the screen assembly is collapsible such that the viewable screenarea is considerably larger when in an open condition than its largestarea of encumbrance when in the closed condition. The resulting assemblyis potentially provided with a portable nature suitable for applicationsinvolving carrying from room to room or travelling from place to place.

It may be desirable for the screen to have a joint-less configuration onits viewable surface and to this end the assembly uses a screen memberof a flexible nature, with the screen member comprising a flexiblematerial.

The material of the screen member may be of a passive translucent naturesuitable for the diffusion of optical images projected through thescreen from a projection device located to the rear of the screenmember.

The screen assembly may be composed of a screen member retained within ascreen frame member having jointing means thereon (such as hinges or thelike) such that any section of the screen assembly may fold about one ormore axes determined by the jointing means in such a manner as tosignificantly reduce the screen member area when in the closed position.

The screen assembly and jointing means are preferably so configured thata screen and frame section (as determined by the frame jointing meanssuch as hinges) may rotate or fold about the jointing means such that ascreen section through approximately 180 degrees into a flat positionadjacent to other screen and frame sections.

The screen assembly and jointing means are preferably so configured thatthe screen and frame sections may rotate or fold about the jointingmeans such that a screen section lies substantially perpendicular toanother or several other screen and frame sections.

For example, the screen and frame sections may rotate by jointing meansabout the frame axis enabling outer screen sections to rotate so thatthe said outer sections are perpendicular to the remaining screensections when in the closed condition.

The screen and frame sections of the screen assembly may be so arrangedthat sections of the screen assembly are enabled to rotate about atleast two axes one of which is not parallel to any other axis, or atleast two axes of which at least two are essentially parallel, or abouttwo parallel axes and a third perpendicular axis.

The screen frame member may be provided with screen frame supportingpanels or members that are attached by a jointing means to the edges ofthe screen frame such as to provide mechanical support to the screenassembly when in the open condition and to lie flat with the screenmember when in the closed condition. A plurality of screen framesupporting panel members may be provided connected by jointing orhinging means. Some or all of the axes of rotation of the jointing meansbetween frame supporting panels are preferably configured to failessentially parallel and co-incidental or adjacent to axes of thejointing means of the screen assembly when the frame support members areclosed flat against the screen member.

The frame supporting member or panel or multiplicity thereof is or areattached by a jointing means to the frame member and which lies flat andadjacent with the screen member when the screen assembly is in thecollapsed position and deploys in such a manner as to providesubstantial mechanical support to retain the screen assembly in theupstanding position and/or to retain the frame elements in the fullyopen condition for viewing of the screen images.

It is a preferable feature of the aforesaid screen assembly and jointingmeans that they are together configured to avoid or reduce any opticalor physical damage or deterioration to the viewable surface of thematerial of the screen member that may be caused by any position thereofor due to any repeated opening or closing actions.

The jointing means may be configured such that they provide axes ofrotation that are virtual or pseudovirtual or are axes that move out ofthe physical section of the frame elements or jointing means.

Another possible member is a base member that can be placed on a flatsurface and to which the screen assembly and/or any present framesupporting member can be attached such as to be supported in theupstanding position upon or by the base member. This base member may beconfigured as an enclosure preferably with a lid into which the saidscreen assembly can be stored and secured for transport. The base memberif constructed as an enclosure may also contain a media source to storethe images.

Thus, the invention further comprises a portable visual display devicecomprising a screen assembly in accordance with any preceding claimwherein the screen assembly is mounted to a base member suitable forseating on a flat surface such that the base member provides support toretain the screen assembly in an upstanding position when in the opencondition.

Within the context of its use as, or as part of, a visual display devicethen another possible member is a light-imaging means or device capableof creating the display images so.

Another possible member is a projection device whereby the images on thefront viewing surface of the screen are generated by rear projection ofthe images through a translucent screen material suitable for suchpurposes. The projection device may be utilised as an integral,removable or attachable unit and may have associated with it a mirror ormirrors such that the optical light path from the projector can befolded back to thus reduce the physical pat h distance from projector toscreen member.

The apparatus may optionally be provided with a light-shield member thatmay be used with the aforesaid projection device to ensure that ambientlight cannot impinge on the rear side of the screen member to thedetriment of image quality while the screen assembly is operational.This light shield is preferably also collapsible into a much smallerclosed condition either with or separately from the screen assembly.

In a preferred arrangement the light shield is deployable in the opencondition so as to be adjacent or attached to the upper horizontal andthe upstanding frame elements of the screen assembly and to extenddownwards and rearwards towards the base member.

The base member may be configured as an enclosure with a lid such thatthe enclosure lid when open acts as a part of the light shield.

The light shielding member may be jointed to the screen assembly suchthat it is collapsible from the open and deployed condition to acollapsed condition adjacent to the screen assembly, and preferably thelight shielding member or any part or element thereof is jointed to ascreen frame edge and acts as a frame supporting panel such as providemechanical support to the screen assembly when in the open position.Also the light shielding member or any part or element thereof may actas a fold guide element that can be brought into a position adjacent andparallel to the axis of rotation of the screen assembly sections such asto act as a support or guide to the screen member material as it wrapsaround the fold guide elements during the rotation of the screenassembly sections during the closing actions and when in the closedcondition.

A particular embodiment of the invention utilising a projection devicecan form a configuration that enables the screen and light shield memberto be attached together by jointing means enabling them to open andclose integrally as a single entity and to preferably collapse into theaforesaid enclosure. The light shielding member may be configured tocollapse in a secondary collapsing movement in co-operation with thecollapsing movement of the screen assembly such that the combined devicecollapses to a closed condition, and in such an arrangement the axes ofcollapsing of the light shielding member are preferably parallel andadjacent or co-incidental.

It is desirable that each or all of the aforesaid members or elementsmay be considered as “self-collapsing”, that is to say can be deployedwithout need for user intervention to deploy or collapse the assembly orcombined assemblies other than by a direct action only to open or close(or short series of simple actions in the case of combined assemblies)or by actuation of a mechanical or motorised drive to perform the same.

Other alternative features of the invention will be apparent from theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective drawing that shows an example of a generalvisual display screen assembly.

FIG. 2 is a perspective view of two embodiments including a single axisof rotation.

FIG. 3 is a perspective view of two embodiments including two axis ofrotation of which both are, in the examples shown, parallel to oneanother.

FIG. 4 is a perspective view of two embodiments including two axis ofrotation of which both are parallel to one another and whereby the outersections of the screen assembly are not overlapping.

FIG. 5 shows a perspective view of a general screen assembly utilising arigid screen member in accordance with prior art arrangements.

FIG. 6 is a cross-sectional plan view of the general assembly of FIG. 5in accordance with prior art arrangements.

FIG. 7 is a cut-away perspective of a possible simple embodiment of ajointing means.

FIG. 8 is a cross-sectional view of a preferable embodiment of ajointing means that has a combined linear and rotational action thatprovides an action similar to a virtual axis of rotation outside of thephysical frame elements.

FIG. 9 is a cross-sectional drawing that shows another embodiment of ajointing means that achieves the same result as that shown in FIG. 8.

FIG. 10 is a cross-sectional drawing that illustrates the aboveembodiment of FIG. 9 with screen frame element rotated through 180degrees.

FIG. 11 is an exploded and partially cut-away perspective drawing thatillustrates an embodiment of the detail of the jointing means asillustrated in FIGS. 9 & 10.

FIG. 12 is a detailed cut-away perspective view of the jointing means asdescribed in FIGS. 9, 10 & 11.

FIG. 13 is a perspective view similar to FIG. 12 and showing only thescreen element, its attachment members and a further optional fold guideelement.

FIG. 14 is a cut-away perspective view of another embodiment of ajointing means using only folding methods.

FIG. 15 is a perspective view showing in more detail an embodimentsimilar to the upper embodiment of FIG. 4.

FIG. 16 is a perspective view similar to FIG. 15 whereby frame supportpanel members are shown.

FIG. 17 is a perspective view similar to FIG. 16 that shows the screenassembly retracted back to be adjacent to the front edge of the basemember.

FIG. 18 is a perspective view of an embodiment of a visual displaydevice similar to FIG. 17 but using a screen assembly with two parallelaxis of collapsing and with a screen member of a material suitable forrear projection.

FIG. 19 is a perspective view of the same device as in FIG. 18 wherebythe screen assembly is shown folding downwards towards the screenassembly.

FIG. 20 is a perspective view of the same device as in FIG. 19 wherebythe top light shield member has folded downwards against the screenassembly.

FIG. 21 is a perspective view of the same device as in FIG. 20 wherebythe screen assembly sections and light shield sections have rotatedabout the two parallel axis to approximately 90 degrees.

FIG. 22 is a perspective view of a collapsed screen assembly similar tothat presented in previous figures and using two parallel axis ofcollapsing with a further set of hinge elements that define a third axisperpendicular to the two existing parallel axis.

FIG. 23 is a perspective view similar to that of FIG. 16 thatillustrates a further embodiment of the invention whereby the topsection of the screen assembly can hinge down as a secondary collapsingaction.

FIG. 24 is a perspective cut-away view similar to that of FIG. 13 thatillustrates a further embodiment of the proposed fold guide elements.

FIG. 25 is a cut-away and exploded perspective view of part of thescreen member and the fold guide elements at the critical positions.

FIG. 26 is a perspective view of the screen assembly being attached byjointing means at its lower edge to a base member.

FIG. 27 is a perspective view showing a frontal view of the screenmember in the open condition. A light shield member is also shown.

FIG. 28 is a view similar to that of FIG. 27 but from a rearperspective.

FIG. 29 is a view similar to FIG. 28 but with the light shield membermoving to the collapsed condition.

FIG. 30 is a view similar to FIG. 29 and with the light shield memberfully folded against the rear face of the screen assembly.

FIG. 31 is a horizontal cross-sectional view through the lower framemember.

FIG. 32 is cross-sectional view along a vertical plane passinglongitudinally through the centre of a device similar to that asdescribed in FIG. 27 and exposing by way of example a suitable internalarrangement of the device.

FIG. 33 is a possible embodiment showing the visual display deviceincorporating an audio system and “plug-in” modules to provide imagemedia such as by a DVD player or Television tuner or PCM card similarmedia source and a removable projector unit.

DETAILED DESCRIPTION OF THE INVENTION & ILLUSTRATED EMBODIMENTS

FIG. 1 is a perspective drawing that shows an example of a generalvisual display screen assembly wherein a rectangular supporting framemember (1-1) supports the screen member (1-2) that is permanentlyattached (except for replacement purposes) to the surrounding framemember. The screen member is held to be flat within the frame member(1-1) by its being attached to the four sides of the frame member. Theframe member can be considered to comprise the two upstanding sideelements and the upper and lower horizontal elements. A magnifiedcross-section of the frame and screen members is shown for clarity andillustrates a simple example attachment method using a push-in mountingof the screen member into a slot in the frame member.

The material of the screen member may be of a passive translucent naturesuitable for the diffusion of optical images projected through thescreen member from a projection device located to the rear of the screenmember.

Embodiments of a collapsing screen assembly based on the generalassembly shown in FIG. 1 can be configured to have many different closedconfigurations that may include single or multiple methods of movementsuch as linear or rotational movement or any combination thereof andwhereby rotational movement may include single or multiple axis ofmovement that may or may not be perpendicular or may or may not beparallel to each other. Further, in the case of rotational movement, theaxis of rotation may be about a physical axis or a virtual axis ofrotation and may permit rotation through a range of angles.

Possible embodiments of a collapsing screen assembly are demonstrated byway of example but are not limited to the configurations as shown in thefollowing FIGS. 2 through 4 wherein the possible closed conditions areshown and the original open position of the screen assembly is indicatedby a dashed line. Arrows indicating the direction of movement areomitted as this is considered obvious however the screen member surfaceis indicated by a light dashed “Z” shape to clearly identify itspresence.

The following FIGS. 2, 3 & 4 are by way of illustration of the possibleopen and closed configurations as may be applicable to screen materialof a flexible nature.

FIG. 2 is a perspective view of two similar embodiments with acollapsing action about a single axis of rotation. The upper shownembodiment (FIG. 2A) has an upstanding axis of rotation (A—A) and thelower shown embodiment (FIG. 2B) a horizontal axis of rotation (B—B).

FIG. 3 is a perspective view of two similar embodiments with acollapsing action about two parallel axis of rotation. The upper shownembodiment (FIG. 3A) is an example with the outer sections of the screenassembly (3-1) & (3-3) rotated to 90 degrees to the central section(3-2)—such a configuration may be used where the screen assemblysections are required to be closed to a position adjacent to the sidesand top of an enclosure. The lower shown embodiment (FIG. 3B) is.similar to the upper shown embodiment except that the outer sections(3-1) & (3-2) rotate through approximately 180 degrees between open andclosed conditions. As a result said sections (3-1) & (3-3) overlap suchas to be partially super-imposed in the closed condition so as to lierelatively flat. Such a configuration may be preferable for wider screenformats.

FIG. 4 is a perspective view of two similar embodiments with acollapsing action about two axes of rotation of which both axis areparallel to one another and whereby the outer sections of the screenassembly are not overlapping in the closed condition. The upper shownembodiment (FIG. 4A) is an example wherein the outer sections of thescreen assembly are rotated by 180 degrees. The lower shown embodiment(FIG. 4B) is similar to the upper shown embodiment but with a furtherhorizontal axis of rotation (C—C) traversing the upstanding frame sideelements and thus permitting the upper section of the screen assembly torotate to 90 degrees (as shown) relative to the lower section or couldbe rotated further to an angle of 180 degrees (shown in a laterexample).

Referring to FIGS. 2 through 4, it can be understood that in all of theembodiments presented either side of the screen element could beconsidered as the front or the rear side from the point of view ofviewing and that the operations of the embodiments are also valid hadthe axis been located at a disposition at 90 degrees to those shown.

The following FIGS. 5 & 6 are out-with the scope of this invention as itcomprises a rigid or semi-rigid screen material but is shown toillustrate the difficulties of converting the prior art relating torigid screen technologies to flexible screen use.

FIG. 5 shows a perspective view of a screen assembly in accordance withprior art arrangements with a rigid frame member composed of theupstanding frame elements (5-9) and (5-10), the lower frame elements(5-6), (5-7) and (5-8), and the upper frame elements (5-1), (5-2) and(5-3) and having inset a screen member (5-12). The outer screen assemblysections may rotate about the axis (A—A) and (B—B) as indicated by thearrows due to jointing means (5-5) between frame elements (5-1 to 5-2),(5-2 to 5-3), (5-6 to 5-7) and (5-7 to 5-8) and whereby there is aphysical joint in the screen at the positions shown (5-4) & (5-11).

FIG. 6 is also in accordance with prior art arrangements and is across-sectional plan view of the assembly of FIG. 5 along the planedefined by axis (C—C) & (D—D) in FIG. 5. The rigid screen elements(6-12) are shown with the two outer sections rotated throughapproximately 180 degrees to be adjacent to the central section (6-7) asalso previously shown in FIG. 3B. The superimposition is aided by use oftapered frame elements (6-6), (6-8), (6-9) and (6-10) and jointing means(6-5) of different offset at each side. This configuration is simple andis suitable for all screen formats and particularly wider screens (suchas 16/9 formats) but has the disadvantage of having joint lines on theviewable screen area.

The subsequent figures refer to embodiments that avoid such joints onthe viewable screen face by the use of a seamless flexible screen.

In reference to the collapsing actions shown in the basic embodimentsrepresented in FIGS. 2 through 4, it will be evident that furtherrefinements are desirable to assure longevity of a flexible screenmember under repeated opening and closing actions. Such refinements areillustrated in the embodiments shown in FIGS. 7 through 13.

FIG. 7 is a cut-away perspective that shows by way of example a possiblesimple embodiment of a jointing method wherein a section of the lowerframe member comprises of frame elements (7-1) & (7-2) that areconnected by a simple hinge mechanism element (7-3) along the axis(A—A). A slot exists in the frame element and is situated above hinge(7-3) at the position indicated by arrow (B). The flexible screen member(7-5) is of a flexible material that is attached to screen attachmentmembers (7-6) and together can then be attached to the frame via theslot at (B) and locked in place by any appropriate means (not shown inthe figure for clarity). The screen member (7-5) extends upwards towardsthe top of the screen member where the upper frame elements (not shown)contain the opposing hinge elements situated on the same axis (A—A). Theupper elements are arranged in a similar but inverted manner. It cantherefore be noted that the screen member in this case does not extendacross the hinge elements.

In reference to FIG. 7, there is a potential disadvantage to thisconfiguration in terms of longevity and reliability as there is bynecessity a break in the attachment members (7-6) and the screen member(7-5) at the position (D) to enable them to open with the frame elements(7-1) & (7-2). This creates a localised stress and possible fatiguepoint at position (D) of the screen member that may cause deteriorationor tearing of the screen due to repeated opening or closing and/or bythe additional stress caused by the increased tension of the screenmember at position (D) as the two elements (7-1) & (7-2) initiallyseparate longitudinally to commence their rotation to the closedposition. This situation is shown in the lower encircled schematic thathas been added for clarity and indicates this increasing gap asidentified by the arrow (C). A desirable configuration is thereforerequired whereby the stress at (D) is reduced to an acceptable levelthus requiring that the gap at arrow (C) will not occur or will beconsiderably reduced and/or that any stress is distributed over a largerarea and/or a durable support may be added to the screen member at (D)that will not be visible or deteriorate the screen image quality.

A solution to the aforesaid disadvantage can be that the frame membercan be much thicker in the vertical plane of the example shown such thatthe hinge mechanism can be retained towards the outside of the saidframe thus permitting a larger area of screen located behind the frameand permitting that additional support can be added. However thisthicker screen has other disadvantages due to the additional volume andmass of frame to be collapsed and stored. A preferable embodiment iswhereby the screen member is extended past the hinge mechanisms to be,attached towards the outside of the screen frame and thus distributingany screen member stresses or fatigue over the larger area now presentand immediately adjacent to and behind the frame member and alsoenabling that additional support can be attached to this same area whereit will not be visible to a viewer. However a requirement of thisconfiguration is that the frame member, its elements and the hinging orfolding methods or mechanisms should be essentially contained within thesaid members or elements with no protrusion when in the open conditionthat may disturb the visible planarity of the screen member.

Therefore jointing methods or mechanisms are preferred that haveessentially no protrusions outside of the frame elements when the screenmember in the open condition yet permits rotation of frame elementsrelative to each other by up to 180 degrees by creating a real axis thatcan move outside of the frame section or by a virtual axis of rotationout-with the frame member section and also whereby the increasing gap atthe initial movement from the screen member open condition towards theclosed condition—as shown previously in FIG. 3—will not occur or will besignificantly reduced.

FIG. 8 is a cross-sectional view of an example embodiment of a jointingconfiguration that combines linear and rotational means to provide anaction similar to a virtual axis of rotation present outside of thephysical frame elements. The example shown is of a mechanism combining asliding and hinging action that is contained entirely within the screenframe without protrusion when the screen member is in the open conditionand has a reduced gap that opens at the initial closing movements of thescreen member. The screen frame elements (8-1) & (8-2) are shown to bepartially rotated from an initial in-line position towards a finalpossible angle of 180 degrees to a position where (8-1) & (8-2) areadjacent and essentially parallel but not necessarily touching. Thisembodiment uses a hinge type of element (8-3) that is composed of 2 ormore parts that have a common central axis (8-4) and where the parts arealternately connected at one end to either the fixed axis (8-6) of (8-1)and at its opposite end to the sliding and pivoting axis (8-5) of (8-2)or the alternate part is connected at one end to the fixed axis (8-6) of(8-2) and its opposite end to the sliding and pivoting axis (8-5) of(8-1). This example embodiment then permits that the hinge element (8-3)can pivot and partially slide its axis (8-4) outside of the frameelements thus permitting rotation of up to 180 degrees between frameelements (8-1) and (8-2) thus acting as if pivoting (8-1) and (8-2)around a virtual axis outside of the frame elements.

FIG. 9 is a cross-sectional drawing that shows another embodiment by wayof example of a jointing method that achieves the same result as shownin FIG. 8, is mechanically simpler as sliding motion is not required andhas no increasing gap as also described in FIG. 8. This example methodoperates by the use a single hinge element (9-3) with two parallel axis(9-4) raising perpendicular out of the plane of the drawing such thatboth elements (9-1) & (9-2) can each rotate independently throughessentially 90 degrees relative to hinge element (9-4) thus acting as asingle virtual axis of rotation that moves outside of the frame elementcross-section. Element (9-5) is the screen member in cross-section.

FIG. 10 is a cross-sectional drawing that illustrates the aboveembodiment of FIG. 9 with screen frame element (10-2) rotated through180 degrees relative to screen frame element (10-1) and also shows thatthe screen member material is constrained to move into a lightly rolledor folded position between elements (10-1), (10-2) & (10-3) and wherebythe hollow of the hinge element (10-3) is sufficient to avoid pressureor friction against the screen material.

FIG. 4 and FIG. 10 when viewed together demonstrate how the material ofthe screen member (10-5) being held between the upper and lowerhorizontal frame elements is therefore constrained to fold in a similarmanner along lines approximately adjacent to the principal axis ofrotation shown as (A—A) & (B—B).

FIG. 11 is an exploded and partially cut-away perspective drawing thatillustrates an embodiment of the detail of the jointing means asillustrated in FIGS. 9 & 10. The screen element (11-5) can be affixed,folded over or bonded to the screen attachment elements (11-6) that canbe of a form similar to that shown by either (6A) or (6B). The combinedelements of (11-5) and (11-6) can then be located into the screen frameslot as indicated by the arrow (C) of the drawing and if necessarylocked in place by other means such as screws (not shown for clarity).Also shown is an optional additional supporting element (11-7) that isalso flexible but may be of a stiffer and very durable nature and thatmay be integral with, or bonded to, the screen member to provideadditional mechanical support to the screen element across the gap ofthe joint between frame elements (11-5).

FIG. 12 is a detailed cut-away perspective view of the assembled hingeassembly as described in FIGS. 10, 11 & 12.

FIG. 13 is a perspective view of the same assembly as FIG. 12 and showsfor clarity only the screen element (13-5) and a further optional foldguide element (13-7). The intention of this optional fold guide elementis that as the screen member moves to the closed condition, the foldguide element will provide additional support to the material of thescreen member along the fold line (A—A). As the said screen membercloses, the screen material therefore wraps-around the contoured edge(B—B) of the fold guide element and is thus retained in the appropriateshape and contour of the support.

The above example embodiments of the jointing methods, have all usedsliding or hinging actions or a combination thereof by way of example.The following is a different approach using folding methods.

FIG. 14 is a cut-away perspective view of an example embodiment ofjointing methods using only folding methods. In this example the framemember consists of an essentially in-extensible but flexible supportingband (14-3), the frame elements (14-1) & (14-2) and the optionalmultiple segments, of (14-4). These elements can be either bondedtogether or made as a single integral flexible part. The elementstogether effectively operate as a continuous hinge across the locationbetween the rigid sections of frame elements (14-1) & (14-2) and wheremay be located the segments (14-4). The screen member (14-5) is attachedor bonded to the band (14-3). Where segments (14-4) are used then atension spring member (14-6) may pass through the segments (14-1),(14-4) and (14-2) such as to retain the frame elements in the openposition and ensure that the curvature between each of the elements isuniform when in the closed position.

The following FIGS. 15 through 21 demonstrate by way of example,embodiments of the screen assembly and their use as part of a visualdisplay device using jointing means as shown in the preceding figures.

FIG. 15 is a perspective view showing in more detail an embodimentsimilar to the upper embodiment of FIG. 4 in the open condition andwherein four jointing means (15-4) are included to permit a collapsingaction around axis (A—A) and (B—B) of the outer frame sections (15-1) &(15-3) and the central section (15-2). A base member (15-6) that acts asa support to retain the screen assembly in the upstanding position isalso shown. This base member is also configured as an enclosure. Twopossible different closed conditions of the screen sections are shown.In the first, one of the screen assembly outer sections is rotated to 90degrees as in (15-1) such that when the entire screen assembly isfurther collapsed towards the enclosure base member about jointing means(15-7) between the base and screen assembly, then the outer screensection falls parallel and adjacent to the sides of the enclosure.Depending on configuration, the outer screen section may be inside oroutside of the enclosure. The second possible closed condition iswhereby the outer screen sections—as shown by (15-3) that is rotatedthrough 180 degrees such as to be adjacent to the central screen section(15-5).

It can be noted that in all of the simple embodiments shown in FIGS. 2through 4, the screen assembly is likely to require other support toprevent the frame member trying to collapse itself back into the closedcondition. A mechanical support is required for the frame elements orhinges to properly maintain the screen assembly in the open condition.This can be of many forms such as locking mechanisms or the addition ofsimple spring action within the frame elements to maintain the screenassembly planar and open for viewing. Mechanical support may also beprovided by attached panels as is shown in the following embodimentusing frame supporting panels.

FIG. 16 is a perspective view of the same device as FIG. 15 in whichframe support panel members (16-8, 16-9, 16-10, 16-11, 16-12, 16-13,16-17) are provided and are attached by jointing means along their frontedge to the side upstanding frame element of the outer screen section(16-1) and the upper horizontal frame elements of the screen centralsection (16-2). The frame support panels may be of a rigid or semi-rigidnature and composed of several sections attached by jointing means alongjoint lines (as indicated by long dashed lines when not folded and solidlines when folding or folded). The figure also shows that the screenassembly may be mounted on jointing means (16-7) to sliding elements(16-14) and that the lower edge of the screen supporting panels areattached by jointing means to side arms (16-15) that rotate out from thesides of the base about their attachment points (16-16). As is shown byFIG. 16, when the screen assembly is fully advanced on the slideelements (16-14) away from enclosure, then the side supporting panels(16-8) & (16-17) are constrained to move outwards by reason of thesupport panels being attached to the side arms (16-15) that are in turnconstrained to pivot outwards. This action pulls the side frame supportpanels fully open and will constrain the upper frame supporting panels(16-9, 16-10, 16-11, 16-12, 16-13) to move to a common planar positionthat will effectively support and retain the screen assembly sections intheir fully open position and prevent the screen assembly sections fromcollapsing to the closed condition. It can be noted that the side panelsmay be used to provide support via the side arms (15) to retain thescreen assembly in an upstanding position.

FIG. 17 is a perspective view of the same device as in FIG. 16 wherebythe screen assembly is retracted back to be adjacent to the front edgeof the base member (17-6). Viewing FIGS. 16 & 17 together, the framesupporting panel elements (17-8, 17-10, 17-11, 17-12) have beencollapsed against the screen assembly. The side arms (17-15) areretracted into the base member and their attachment point (17-18) to theside frame supporting elements (17-8) & (17-17) fall adjacent to theaxis of the jointing means between the base member and the screenassembly. The joint lines between the upper frame supporting elements(17-10 to 17-11) and (17-11 to 17-12) as shown in FIG. 17 areimmediately adjacent to the axis (A—A) and (B—B) thus permitting thatthe screen assembly and frame supporting panels may now be collapsedthrough 180 degrees along the axis (A—A) and (B—B) to the closedcondition. The collapsed screen assembly can now be further collapsedaround the axis of the jointing means at (17-7) to move from itsupstanding position to be enclosed within the base member.

FIGS. 18 through 21 shows an embodiment of the invention utilisingimages generated by rear projection methods and where the screen framecontains two parallel axis for the collapsing of the sections of thescreen assembly. The principles of the light shield member (as may berequired in rear projection) and the base/enclosure member are alsointroduced and a further use of the side arms is demonstrated.

FIG. 18 is a perspective view of an embodiment of a visual displaydevice similar to FIG. 16 but using a screen assembly (18-1) with twoparallel axis about which the assembly collapses and with a screenmember (18-1) of a material suitable for rear projection. A base memberconfigured as an enclosure member (18-3) with lid (18-5) and a lightshield member are also shown. The purpose of the light shield member isto eliminate or reduce the ambient light that may impinge on the rearside of the screen member when a suitable screen is employed for rearprojection methods. The light shield may consist of an upper element(18-4), two side elements—only one side shown (18-2) and a rear elementthat in this case is represented by the enclosure lid (18-5). The lightshield may be constructed to be of any suitable form or material that isfit for this light shielding purpose and is preferably of a collapsiblenature by jointing means between the light shield sections. In the FIG.18 the fold lines are shown as dashed lines when unfolded and as solidlines when folded.

It can be noted that the side elements of the light shield may beattached by jointing means along their lower side edges to the side armsthat were shown in the previous example embodiment. The front edges ofthe top and side light shield elements are attached to the screenassembly by jointing means and the front sections of the light shieldoperate identically to the frame supporting panels of FIGS. 16 and 17and thus effectively replace these frame supporting panels in their useto support the upstanding screen assembly and also retain the screenassembly sections in their open position. It is a further preferablefeature that the light shield member is also collapsible and further, itis preferable that the collapsing action of the light shield is of anintegral manner therefore not requiring any addition or connection,removal, disconnection or re-location of any parts thereof. It is afurther preferable feature that if the light shield is initiallycollapsed against the screen member such that the light shield may thencollapse in an integral manner with the screen assembly towards and intothe base member—and thus reducing the actions required to collapse thecombined assembly. The following figures further demonstrate suchembodiments.

FIG. 19 is a perspective view of the same device as in FIG. 18 wherebythe top light shield element is hingeably attached to the top edge ofthe screen assembly along its front edge and is shown folding downwardstowards the screen assembly. As it does so, the folding action alsocauses the front section of the side light shield element (19-2) to foldinwards about its attachment edge with the side of the screen framemember in a similar manner to that shown in FIGS. 16 and 17. This actionwill also permit that the screen assembly will retract rearwards towardsthe front top edge of the enclosure member (19-3) and the sides of thelight shield member (19-2) will be moved inwards as the side arms,similarly to that of FIGS. 16 and 17, will retract into the sides of theenclosure (19-3).

FIG. 20 is a perspective view of the same device as in FIG. 19 wherebythe top light shield member (20-4) has folded downwards against thescreen assembly and in doing so has folded completely the front sectionof the side light shields (20-2—not shown) behind and against the screenassembly into a position similar to that of FIG. 17. It may be notedagain that as in the device explained in FIG. 17, the fold lines of theupper element of the top light shield element should be immediatelyadjacent to the parallel fold lines of the screen assembly as prescribedby the screen frame axis and thus permitting the combined light shieldand screen assembly to fold together in the direction of the arrowsindicated to a closed position at 90 degrees to the original openposition.

FIG. 21 is a perspective view of the same device as in FIG. 20 wherebythe screen assembly sections and light shield sections have rotatedabout the two parallel axes to approximately 90 degrees. The combinedlight shield and screen assembly can now be collapsed again into itsfinal position adjacent to the enclosure by hinging rearwards about thejoints connecting it (via the slide elements similar to FIG. 16) to thebase member (21-3). When collapsed completely, the outer sections of thescreen assembly will be adjacent to the outer surface of the sides ofthe enclosure (21-3) and the central section of the screen assembly(21-1) is adjacent and approximately flat and parallel with the top ofthe enclosure (21-3). The means of collapsing of the remaining sidesections of the side light shield elements (21-5) can be of many formsand an example of this can be by a simple concertina folding actiondefined by fold lines forming triangular elements with a common apexco-incident with the axis of rotation of the screen assembly. The lid ofthe enclosure can be configured so as to partially or completely enclosethe screen assembly when the lid is itself closed.

It is desirable in any screen member embodiment that it will permit thescreen assembly to collapse or deploy in an integral and self-supportingmanner. FIGS. 15 through 21 show that the screen assembly (and anyattachments thereto i.e. the light shield) can move as a completeassembly between the open condition and the closed condition and do soby a single action or short series of actions that relate only anddirectly to the opening or closing actions and without need for anydisconnection or detachment or removal or re-location or addition orconnection or re-connection of any element or member. Means such asspringing action may be included further assisting the individualassemblies or frame supporting panel elements to be self-supporting.

With particular reference to the embodiments described in FIGS. 15through 21, it can be further noted that opening or closing actions ofthe screen assembly of the invention can be executed by userintervention or by inherent mechanisms (such as springs) or by anexternal drive (for example by means of motorization) that may also beattached to the base member or enclosure to further maintain or controlthe position of the frame supporting elements or be used for motorisingthe action of opening or closing the screen assembly and/or light shieldassembly.

The next series of figures demonstrate the use of non-parallel axis offolding of the screen assembly and example embodiments.

FIG. 22 is a perspective view of a collapsed screen assembly similar tothat presented in previous figures and using two parallel axis ofcollapsing. Also indicated are a further set of hinge elements (22-4)that define a third axis (C—C) perpendicular to the two existingparallel axis.

FIG. 23 is a perspective view very similar to that of FIG. 22 thatillustrates a further embodiment whereby the top section of the screenassembly (23-3) can hinge down as a secondary collapsing action andwhereby the further folding action occurs about a further axis (C) thatis at 90 degrees to the original two parallel axis of collapsing. Thissecondary collapsing action can be performed by use of jointing means at(23-4) that may have features similar to those illustrated in FIGS. 7through 13. The arrow (23-5) represents the movement downwards from theoriginal position at a 90 degree position (A) and this movement may becontinued down to a final position—shown by the dotted lines (B). Thescreen fold edges have potential pinching or crushing points that mayoccur on the fold lines (23-6) and (23-7) of the screen member (23-6)due to this secondary rotation towards the final closed condition.

In reference to FIG. 23, it is evident that additional support to thescreen member is required in the case of the above described secondarycollapsing condition to avoid pinching or crushing actions and thissupport can be similar to or based on the principals outlined within thedescription of FIG. 13 with an additional means to be described in thefollowing figure.

FIG. 24 is a perspective cut-away view of an arrangement similar to thatof FIG. 13. This illustrates a particular further embodiment of theproposed fold guide elements (24-1) whereby it can be composed with adifferent material, thickness or physical configuration such that aflexible section (24-2) of the fold guide elements may easily bendaround a virtual axis (A—A). This axis and thus the flexible section(24-2) should be located as part of the fold guide elements (24-1) suchthat this position coincides with the line of folding of the screenmember material (24-3) such as to be adjacent to the axis (C—C) of FIGS.22 and 23 and thus situated between the points (24-6) to point (24-7) ofFIG. 23.

FIG. 25 is a cut-away and exploded perspective view of part of thescreen material (25-3) and the screen material support (25-1) at thecritical positions shown as Points (25-6) & (25-7) of FIG. 23 due to theaction. of the secondary collapsing action as described in FIG. 23. Thescreen material (25-3) and screen material support member (25-1) are inreality in contact but are shown to be separated in this figure forreasons of clarity. A grid has been drawn for clarity on the surface ofthe flexible section (25-2) such that the resulting shape of the foldguide elements is understood and the form that the screen material willadopt along the fold line (C—C) at the contact with the contoured edgeof the screen material support member (B—B).

The jointing means (23-4) of FIG. 23 can be of a similar nature to thosedescribed in FIGS. 9 through 13 but large enough to accommodate theouter diameter of curvature of the screen and screen material supportmembers when in the closed condition as shown in FIG. 25.

Referring to the screen material (25-3) shown in FIG. 25, the inner andouter radii of curvature, the flexibility of the screen element and itstension within the collapsed frame should be such that the additionaltension of being stretched over the outer surface of the folded section(25-2) will not cause optical or mechanical damage to the screen elementand also that the reduction in tension on the inside surface of thefolded section (25-2) will not permit undue wrinkling or pinching of thescreen material.

FIGS. 26 through 30 provide an example embodiment of a screen assemblyhaving two parallel axis and a third perpendicular axis of collapsingand its use within a visual display device being activated by rearprojection methods.

FIG. 26 is a perspective view of a screen assembly similar to that shownin FIG. 22 being attached by jointing means on its lower side to a base(26-1) that can be positioned on a flat surface and is used to maintainthe screen assembly upstanding when in the open position. This viewshows the base may also be in the form of an enclosure with a lid (26-2)(shown in partial out-away).

FIG. 27 is a perspective view of the same device as FIG. 26 showing afrontal view of the screen member (27-5) in the open condition. A lightshield member is shown to be attached or adjacent to the frame member(27-3) and extends rearwards and downwards to be attached or adjacent tothe base member (27-1) by means of its sides (27-7) & (27-9) and top(27-8). As explained previously in FIGS. 18 and 19, the front sectionsof the top and side light shield elements due to their being in a commonplane and at an angle to the frame hinging axis effectively act as framesupporting panels and also assist in retaining the frame and screenassembly sections in their open position. If the base (27-1) isconfigured as an enclosure, it can be seen that where a lid of theenclosure is present and supported by the addition of hinging mechanismsto the rear of the enclosure (27-4), then the said lid may be used toact as the rear section of the light shield member and/or as a supportthereto.

In further reference to FIG. 27 it can be noted that in the situationwhere the base member (27-1) is configured as an enclosure then thisenclosure may also retain the projection device for rear projectioneither integrally within the enclosure or as a removable unit or as anattachment to the said base or enclosure member. The inner surface ofthe rear light shield or lid member (27-2) may support or have affixedto its inner surface a mirror member (27-6) to reflect images from theprojector unit to the screen member. In the case of the projector beingintegrally mounted within the enclosure member, then an aperture (27-10)can be mounted in the enclosure such that a mirror affixed to theaperture will direct the light path of the projector to the screenmember, possibly via another mirror, when the aperture is closed andwhen open will permit that the light path of the projector be allowed toexit the enclosure for front projection on a remote surface.

FIG. 28 is a view of the same device as in FIG. 27 but from a rearperspective and shows enclosure (28-1) and that the lid of the enclosure(28-2) that also act as part of the light shield member (28-3). Thisembodiment will, in the following figures, demonstrated further exampleof an integrally collapsing light shield member (however different inconfiguration from the previously shown embodiment of FIG. 16) wherebythe folding or hinging action occurs along the folding lines indicatedin the drawing by long dash lines (until folded it is thereafterrepresented by a solid line). The following figures describe theoperation of this collapsing light shield member and how it alsocollapses integrally with the screen assembly.

FIG. 29 is a view of the same device as in FIG. 28 but with theenclosure lid (29-2) partially cut-away for clarity and showing thelight shield member elements (29-1 through 6, elements on the remoteside of drawing are symmetrical positioned but not identified forclarity). The upper light shield elements (29-4), (29-5) & (29-6) areattached to the corresponding elements of the upper frame elements(29-7). The front edges of light shield element (1) are attached to theupstanding side frame element (29-8). The side faces of the light shieldmember (29-1) & (29-2) when drawn towards the screen member as shown bythe arrows, will cause the upper side light shield element (29-3) tofold inwards around the upper edge that is attached to the outer edge ofupper element (29-4). This action also causes the light shield elements(29-4), (29-5) & (29-6) to rotate around their common axis of attachmentwith the top of the screen member (29-7) and thus rotate in a downwarddirection and thus also towards the rear face of the said screen member.

FIG. 30 is a view of the same device as in FIG. 29 and with theaforesaid light shield member fully collapsed against the rear face ofthe screen assembly. It should be noted that the fold lines between thelight shield elements (30-1 to 30-2) and (30-4 to 30-5) and also theprevious lower edge of element (30-3) are all parallel and immediatelyadjacent to the axis of folding of the screen assembly. This permitsthat the outer screen assembly sections may still collapse as a combinedscreen assembly and light shield member to a closed condition bycollapsing through 180 degrees about the axis (A—A) and (B—B) in thedirection of the arrows (30-10) & (30-11) to the collapsed configurationsimilarly to that as described in previous figures.

A preferable embodiment of the light shield member would permit that theelements of the light shield when collapsed flat with the screenassembly as shown in FIG. 30 would together form a composite curvedsurface around which the screen element will roll into a fold along theaxis (A—A) and thus act identically to the fold guide elementspreviously described as element (24-1) of FIGS. 24 and 25. The followingfigure further demonstrates how the light shield members by use offolding or flexible areas of their elements can be folded within thecollapsing screen assembly and act as fold guide elements.

FIG. 31 is a horizontal cross-sectional view through the lower framemember according to the direction of arrow (C) of FIG. 30. Thiscross-section is on a horizontal plane and shows schematically the mostcomplex part of the combined collapsed assembly. The figure contains anupper and a lower view of the open and closed conditions respectively.The cross-section of the screen member is shown in black todifferentiate it from the cross-sections of the various other lightshield members in close proximity. For clarity, the areas of the lightshield that are rigid or semi-rigid are shown in single hatching and theareas that are flexible such as the fold area at connection of (31-1 to31-2) and the fold area at the connection of (31-4 to 31-5) are shown bycross-hatching.

Continuing with the closing action of the assembly as described in FIGS.30 and 31, the screen assembly can now be considered to be collapsedalong with the light shield member to its closed condition similar tothat previously shown in FIG. 22. The upper section of the combinedscreen assembly and light shield member can now be collapsed around theperpendicular axis as shown in FIG. 23 by using similar methods ofco-incidental fold lines on the light shield and the methods of FIGS. 24and 25 whereby the light shield effectively takes the place of thescreen material support elements of FIGS. 24 & 25. This actioncompleted, the doubly collapsed combined assembly can now be retractedinto the enclosure member as shown similarly in FIG. 26.

Mechanisms may also be attached to the base member or enclosure tofurther maintain or control the position of the frame elements or beused for motorising the actions of opening and closing of the screenassembly and possibly in combination with the actions to collapse thecombined screen assembly and light shield assembly as described in FIGS.29, 30 & 31.

FIG. 32. is cross-sectional view along a vertical plane passinglongitudinally through the centre of a device that may be consideredsimilar to that as described in FIG. 26 and exposing by way of example asuitable internal arrangement of the device. The screen assemblycomprises of the screen member (32-1) and frame elements (32-2) & (32-3)and is hingeably mounted to the base (32-4) configured as a carryingcase and also containing a mirror (32-5) mounted on an aperture door(32-6), a removable projector unit (32-7), a lid (32-8) to which isattached a further mirror (32-9). The front and sides of the lid (32-10)are attached by jointing means to the main lid section (32-8) such as toextend forward and outwards to act as a part of the existing lightshield (32-11). The case also contains slides (32-12) permitting the lidto slide outwards and rearwards from the case to permit enough distancebetween the screen and projector along the light path (shown as dashedlines). An optional member of the case may be an audio system (notshown) and a module bay (32-14) for media such as for example TV, DVDplayer, memory card (i.e. a PC-Card) or say a disk based memory device.

FIG. 33 is a perspective view of a possible embodiment with the screenmember (33-1) in the open condition and showing the visual displaydevice incorporating an audio system (33-2) and “plug-in” modules (33-3)to provide image media such as by a DVD player or Television tuner orPC-card or similar media source and a removable projector unit (33-4).The format of the enclosure with all elements collapsed therein is shownas item (33-5).

Within the scope of the above described embodiments, “hinges” or“hinging”, “folds” or “folding”, “rotates” or “rotating” can beconsidered to generally refer to mechanisms or any material ormechanical property that permits that members, elements or parts thereofcan move in an rotating manner relative to one another around a commonreal or virtual axis and whereby “slide” or “sliding” can be consideredto generally refer to any material or mechanical property that permitsthat members, elements or parts thereof can move in any linear orlongitudinal manner.

What is claimed is:
 1. A collapsible rear projection screen assembly fora portable visual display device comprising a screen assembly thatcollapses into a closed condition suitable for easy transport by asimple folding movement between two or more screen sections and reducesor eliminates the risk of optical or physical damage to the screenmember during collapsing and achieves these by comprising a flexibleviewing screen member that is held to be flat by its permanentattachment to the four sides of a surrounding rectangular frame memberthat is composed of rigid frame elements connected by jointing means andwhere the jointing means feature axes of rotation that can be consideredto be virtual or pseudo-virtual or that may move out of the physicalsection of the frame elements and thereby permitting rotation in afolding manner of up to 180 degrees between sections of the screenassembly and whereby the viewing screen member and/or its attachmentmeans may extend outwards to at least partially overlap the framejointing means and also whereby the elements of the jointing means bytheir shape or by their operation will provide a hollow into which thescreen member can pass during the rotation of the jointing element tothe closed position and thus avoiding potential damage to the materialof the screen member by crushing or other contact.
 2. A screen assemblyas claims in claim 1, wherein the viewing screen member attachment meansand the screen frame jointing means are essentially contained within ormounted on a rear non-visible surface of the screen frame elements.
 3. Ascreen assembly as claimed in claim 1, wherein the screen membercomprises flexible screen supporting elements that may be additionalparts of integral elements of the screen attachment means that providesupport to the screen member across any gaps in the attachment meansassociated with the jointing means between the screen frame elements. 4.A screen assembly as claimed in claim 1, wherein the jointing means, thescreen frame member and the screen attachment means are configured topermit the material of the screen member to roll into a lightly rolledfold as the screen sections rotate around the axes of the jointing meansto avoid damage to the physical or optical properties of the material ofthe viewing screen member during movement between the open and closedconditions.
 5. A screen assembly as claimed in claim 1, wherein thescreen assembly includes attached fold-guide elements that can bebrought into a position adjacent and parallel to the axis of rotation ofthe screen assembly sections such as to act as a support or guide to thescreen member material as it folds around the fold-guide element duringthe rotation of the screen assembly sections during the closing actionand when in the closed condition.
 6. A screen assembly as claimed inclaim 1, wherein sections of the screen assembly may rotate about atleast two axes of which at least two are essentially parallel.
 7. Ascreen assembly as claimed in claim 1, wherein section of the screenassembly may rotate around two parallel axes and a third perpendicularaxis.
 8. A screen assembly as claimed in claim 1, wherein two axes ofrotation of the screen sections intersect, the fold-guide members areconfigured to fold or bend in a controlled manner and parallel with thesecond intersecting axis of rotation such that the edge of the foldguide member and the screen material that is wrapped around it willcurve into a “U” shape and whereby the edge of the base of this “U”forms an approximately semi-toroidal shape such as to permit the wrappedmaterial of the screen member to effectively fold in two planes withoutpinch points or stress damage.
 9. A screen assembly as claimed in claim1, wherein frame supporting panels are attached by jointing means to thescreen frame elements and each frame supporting panel is connected byjointing means to the neighboring frame supporting panel on the opposingside of each frame joint such that when the frame supporting panels areopened outwards towards an approximate perpendicular position then theconnected frame supporting panels and their jointing means willeffectively lock the screen assembly in the open condition.
 10. A screenassembly as claimed in claim 9, wherein some or all of the axes ofrotation of the jointing means between the frame supporting panelmembers are configured to fall essentially parallel and coincident oradjacent to the axes of the jointing means of the screen assembly whenthe frame supporting panel members are closed flat against the screenmember thus permitting the screen assembly and frame supporting panel tofold together.
 11. A screen assembly as claimed in claim 1, wherein thescreen assembly is configured to deploy to the open condition orcollapse to the closed condition as a complete and integral assembly.12. A visual display device comprising a screen assembly as claimed inclaim 1, wherein the screen assembly is mounted on a base membersuitable for placing on any suitable surface such that the base memberprovides support to retain the screen assembly in an upstanding positionwhen in the open condition and where the base member may also serve ofthe attachment of a projection device.
 13. A visual display devicecomprising a screen assembly as claimed in claim 12, wherein the basemember is configured to serve as a base enclosure member and is hingedlyattached to the screen assembly such that the collapsed screen assemblymay retract into the base enclosure member.
 14. A visual display devicecomprising a screen assembly as claimed in claim 13, wherein the baseenclosure member comprises mechanisms including mechanical or motorisedmeans to assist or execute the opening or closing of the screenassembly.
 15. A portable visual display as claimed in claim 14, whereinthe base enclosure member contains projection means that may beinstalled integrally or installed as a removable unit.
 16. A portablevisual display device as claimed in claim 15, wherein the base enclosuremember comprises a lid to which may be attached a mirror to fold backthe light path such as to reduce the physical distance from theprojection means to the viewable screen member.
 17. A portable visualdisplay device as claimed in claim 1, wherein a collapsible lightshielding member is hingeably jointed to the screen assembly and in theopen position extends downwards and rearwards towards the base member orprojection device and is collapsible by a folding action to an initialcollapsed condition adjacent to the sections of the screen assembly. 18.A portable visual display device as claimed in claim 17, wherein thelight shield member in the initial collapsed condition featuressecondary axis of collapsing that are parallel and also adjacent orco-incidental to the axes of rotation of the screen assembly thuspermitting the screen assembly and light shield member to collapsetogether to the closed condition by a folding action.
 19. A portablevisual display device as claimed in claim 18, wherein the collapsedlight shielding member acts wholly or partially as a fold-guide elementthat is adjacent and parallel to the axis of rotation of the screenassembly sections such as to act as a support or guide to the screenmember material as it wraps around the fold-guide element during therotation of the screen assembly sections during the collapsing actionand when in the closed condition.
 20. A portable visual display deviceas claimed in claim 19, wherein the light shielding members that arejointed to the screen frame edges can act as the frame supporting panelmembers such as to provide mechanical support to the screen assemblywhen in the open position.